Role of Bats in Controlling Agricultural Pests

View the project final report

Commodities

• Agronomic: corn, medics/alfalfa, soybeans
• Animals: bovine

Practices

• Natural Resources/Environment: wildlife
• Pest Management: biological control

Negative effects on environmental quality and human health can be minimized by harnessing natural pest control mechanisms. Natural systems limit 99% of agricultural pests and contribute $54billion - $1 trillion in global pest control services (Naylor and Ehrlich, 1997). Knowledge of natural systems that control arthropod pests can be used to develop strategies that take advantage of natural process that limit pests without the use of pesticides. One natural control of arthropod pests that is possibly undervalued and often overlooked are bats (order Chiroptera). Nearly two-thirds of bat species are voracious predators of arthropods. Many species are known to eat important agricultural pests worldwide (Kunz et al., 2011). One study estimates that bats provide 3.7 – 53 billion US dollars in agricultural pest control across the United States (Boyles et al., 2011) from the direct consumption of insect pests. Estimates of the ecological services provided by bats can be improved by understanding the diet of bats in various geographic regions and crop types.

Corn and Soybeans account for over 50% of cropland acres and 92% of insecticide use in the United States (Pimentel and Peshin, 2014).  However, not studies of diets using modern molecular techniques have examined the diet of bats in these areas. Understanding the diet of bats in this dominant agricultural system can improve estimates of the ecological services provided by bats and reduce pesticide use by informing ways to harness the services of bats. Therefore, we sought to:

• Document the pest species eaten by bats in corn and soybean agriculture
• Quantify the prevalence of agricultural pests in bat diets

We collected bat guano from bats captured near agricultural areas in Lancaster County, NE. We analyzed the insect species present in guano samples using metabarcoding techniques. We then evaluated the pest status and prevalence of observed insect genera to establish pest control potential of bats in the corn belt.

We found that over 90% of big brown bat (Eptesicus fuscus) and red bat (Lasiurus borealis) contained pest species. The most common pest genera found in bat guano included Diabrotica (corn rootworms), Hypena (clover worms), Lygus (plant bugs), Melanotus (wireworms), and Stenolophus (seed corn beetles).

This research documents the agricultural pest diet found in bat diets. Specifically, those insect species that two generalist bat species consume throughout the mid to late growing season were determined.

Although outside the immediate scope of this grant, the ultimate motivation and desired outcome is farmers adopting Integrated Pest Management (e.g., decrease the use of pesticides, increasing bat habitat).  Bat consumption of insects results in increased yields, lower insecticide application and costs, increased profits, greater environmental quality, and improved health and quality of life. Additionally, the results of this study could guide further research.